1. Field of the Invention
The present invention relates generally to medical imaging systems, and more particularly to a method and apparatus for localizing an ultrasound imaging catheter.
2. Description of the Related Art
Medical imaging technology is used to improve the diagnosis and treatment of medical conditions. Presently available medical imaging technology includes a wide variety of ultrasound, X-ray, nuclear, magnetic resonance imaging (MRI) and other imaging systems. A technology of particular benefit to diagnosis and treatment of cardiovascular conditions uses imaging ultrasound detectors mounted a percutaneous catheter.
Techniques exist for localizing catheters deployed within a patient's body. One such technique is described in U.S. Pat. No. 6,192,266 to Dupree (“Dupree” hereafter), which is incorporated by reference herein in its entirety. In particular, Dupree generates an electric field with one of a basket electrode and a roving electrode, the electric field being characterized by the physical dimensions and spacing among the basket electrodes. A navigation application is provided which analyzes the spatial variations in the electrical potentials sensed within the field, and provides a location output which locates the roving electrode within the space defined by the basket, in terms of its position relative to the position of the multiple basket electrodes. Other such systems also exist.
The Dupree system, however, may be problematic in some applications due to its use of an electrode generated electric field to determine the location of the probe. In particular, electric fields generated intra-body can generate electrical currents which flow in the body that may cause muscle stimulation, which may result in heart arrhythmias, etc., when used in or near the heart, such as intra-cardiac sensing or treatment. Thus, a need exists for a non-electric field-based catheter locating system that does not induce significant electric currents in the body. There is also a particular need for catheter locating methods that are compatible with ultrasound imaging catheters, and for methods of utilizing localized position information in combination with image rendering.
Other problems with the prior art not described above can also be overcome using the teachings of the present invention, as would be readily apparent to one of ordinary skill in the art after reading this disclosure.